1. Field of the invention
The present invention concerns a cell comprising a separator comprising a macroporous matrix and a porous polymer and the method of manufacturing it.
2. Description of the prior art
Conventional cells comprise solid electrodes on opposite sides of a separator containing the liquid electrolyte. A separator can be a macroporous body impregnated with the electrolyte, for example. Another, modern type of conventional "separator" is a porous or non-porous gelled polyvinylidene fluoride polymer containing the liquid electrolyte.
Various methods of manufacturing this type of cell have been proposed, including processes involving the separate manufacture of the electrodes and the separator followed by their combination using various techniques. These techniques include rolling (BellCore, U.S. Pat. No. 5,456,000, U.S. Pat. No. 5,460,904, U.S. Pat. No. 5,540,741, U.S. Pat. No. 5,552,239) and adhesive bonding (Electrofuels, U.S. Pat. No. 5,437,692, U.S. Pat. No. 5,512,389).
Also, document U.S. Pat. No. 5,639,573 describes a separator comprising a multiphase polymer support structure comprising at least a porous first phase and a polymer second phase dispersed in the pores of said porous first phase. The dispersed polymer phase absorbs the organic electrolyte; it is not porous.
These techniques are not entirely satisfactory, however, because the separator is sometimes crushed, which causes short circuits. Assembly also requires careful handling.
Moreover, the skilled person is still confronted with the standard problem of the loss of mechanical properties to the detriment of conductivity properties, and vice versa.
An aim of the invention is therefore a new cell comprising a separator having increased mechanical resistance to crushing and enabling easy assembly.